Keywords : artificial life - artificial life research - information - life is all about insuring information is passed on while at the same time preventing entropy from corrupting the message - ALife is showing how the dynamics of information can come to dominate over the properties of the material living things are made of - phase space - Chris Langton -

ARTIFICIAL LIFE

...the continuum of living organism stretches from viruses, which are little more than a stretch of DNA or RNA surrounded by a protein sheath, up to planetary ecosystems like earth at the other. All the use the same principles to defy the first and second laws of thermodynamics and the attempts of the larger universe to return them to the dust from whence they came.

Artificial life research encompasses software simulations, robotics, protein electronics and even attempts to recreate the Earth's first living organism. It is less concerned with what something is built of than with how it lives. It is concerned with dynamics and just how life keeps going. All you, I and everything else need is information.

pg 11

INFORMATION

... Life keeps going using information. The relationship between information and entropy was first discovered by Claude Shannon, an engineer who worked at Bell Laboratories in New Jersey during the 40ies. Shannon is investigating what prevents information being transmitted across a channel or telephoneline. He found that fault lay with the hard to define quality that all this seemed to be increasing whenever information was lost. Shanon never witnessed a decrease in this quality in all the experiments he performed. He called this slippery quality entropy.

Life is all about insuring information is passed on, or transmitted, while at the same time preventing entropy from corrupting the message. Life has found a way to ensure that entropy keeps increasing but not that the expense of its own survival or the integrity of the information it wants to transmit.

This is the biggest and best tricks that life has learned. Now ALife is helping us to understand just how it does it. It is starting to show that living things do not rely on the properties of chemicals to foster another generation, they depend on information encoded in chemical form. ALife is showing how the dynamics of information can come to dominate over the properties of the material living things are made of.

pg 12

CHAOS

THE THREE BODY PROBLEM

...ALife research has revealed that this shift occurs when the system is acting chaotically. Chaos in the mathematical sense. In the real world stability seems to reign. The seasons come and go, our heart keeps on beating and the taps keep dripping but in truth nothing is as safe or secure as it first appears. Living things cannot be captured by equations, they are too messy for that. Intuitively we feel that we have more in common with clouds than clocks and Chaos helps explain why.

Predicting the movement and interaction of two bodies as they orbit the sun is relatively straightforward. Newton solved the mathematics of this problem. You could be forgiven for thinking the mathematics would not get much more complicated if a third body were added. In fact the addition of another object creates an intractable computation known as the n-body problem. The mutual interaction of three bodies around a gravitational centre makes their exact movement impossible to predict. Only in the last decade have researchers been able to use Chaos mathematics to confirm that this is the case. The implication is that the same is true of any system where remarkable forces and influences are at work.

This interplay of objects and forces plays two roles. It keeps the system unpredictable, constantly threatening to upset the apparent equilibrium and plunge it into chaos, but that the same time the push-me-pull-you play of forces keeps it on the straight and narrow. ... The best that can be done is map out all possible outcomes and watch the subject move around the territory to get the feeling for what forces are at work and how they are weighed against each other. These 3-dimensional behavioural maps can be plotted on computer and are said to exist in phase space. You can think of it as a place where anything can happen.

What is becoming apparent is that life has to exist on a knife edge. Observation of fish populations and ant colonies, as well as experiments with artificial creatures, have shown that too much chaos produces a system that never gets a chance to settle down and develop. But if there is too little stimulation, everything stagnates. Between these extremes is a narrow, fertile region where just enough disturbance gets through to keep our heart beating healthily or a populations thriving.

pg 14

LIFE AS A DYNAMIC PROCESS

... this conception of life as a dynamic process - rather than an inherent property of the bits and pieces that living organisms are made of - has only recently begun to prevail. Prior to this change in perception life and living systems were fault by ecologists and biologists to be working toward a static state where environment and organism work in a equilibrium. Now it is known that feedback and conflict is the norm, with specious constantly wrestling for the upper hand and managing to survive and develop together as a result.

This method works because of the realisation that the essential properties of life can be abstracted away from the bustling life we find on earth. In constructing computer models of living things we lose nothing because life is all about the preservation of an abstract property - information. ALife pioneer Chris Langton says: "...the "artificial" in Artificial Life refers to the component parts, not the emergent processes. If the component parts are implemented correctly, the process they support are genuine - every bit as genuine as the natural processes they imitate. The big claim is that a properly organised set of artificial primitives carrying out the same functional roles as the biomolecules in natural living systems will support the process that will be "alive" in the same way that natural organisms are alive. Artificial life will therefore be genuine life - it will simply be made of different stuff that the life that has evolved here on earth."